1. Field of the Invention
The invention relates to a gas filling system that fills gas from a gas station into, for example, a vehicle-mounted fuel tank, and also relates to a vehicle equipped with such a fuel tank.
2. Description of the Related Art
Known gas stations as mentioned above include a hydrogen station that fills hydrogen gas into a hydrogen tank of a fuel cell vehicle (see, for example, Japanese Patent Application Publication No. 2005-069327 (JP-A-2005-069327)) and Japanese Patent Application Publication No. 2007-321572 (JP-A-2007-321572)). In Japanese Patent Application Publication No. 2005-069327 (JP-A-2005-069327), the vehicle and the hydrogen station are electrically connected via an adaptor, and information about the maximum service pressure of the hydrogen tank of the vehicle is grasped at a hydrogen station side in order to control hydrogen filling so that the maximum service pressure will not be exceeded.
While hydrogen is being filled, it is desirable to monitor the temperature and the pressure in the hydrogen tank which rise in association with the hydrogen filling. In conjunction with this respect, consideration has been given to a construction in which, through the use of a communication equipment, signals regarding the temperature and the like in the fuel tank are sent from the vehicle side and the hydrogen station as need arises, and the hydrogen station automatically stops the hydrogen filling before the allowable temperature (reference value) of the hydrogen tank is exceeded (see, Japanese Patent Application Publication No. 2007-321572 (JP-A-2007-321572)).
By the way, the hydrogen filling sometimes requires a long time, depending on conditions. For example, during the daytime under a blazing sun, the hydrogen tank is exposed to an environment whose temperature is higher than normal temperature. If, in view of this situation, the hydrogen filling is performed at slower filling speed than at normal temperature so that the temperature of the hydrogen tank will not exceed its allowable temperature, the filling time becomes long. If during such a long-time filling, data about, for example, temperature in the hydrogen tank, and the like, is transmitted from the vehicle side to the hydrogen station side as need arises, there is a possibility that the electric power source of the vehicle, which is at rest, may lack power.